Currently, the demand for rare earth elements (REE) has increased significantly due to the expansion of volumes and applications in various industries. The annual increase in consumption of specific elements of rare earths is up to 25% per year. To solve the problem of increasing REE production, it is necessary to involve difficult-to-enrich raw materials in processing, which include the weathering mantle of the Kundybay deposit (Kazakhstan). A special feature of this deposit is the increased proportion (54%) of yttrium oxides, medium and heavy lanthanides. As a result of the conducted research, the granulometric and fractional composition of the ore was determined, which made it possible to determine the distribution of REE by the grain-size class of the ore under study. An analysis of the results showed that 29.35% of REE were contained in the grain-size classes more than 0.02 mm, and 70.65% of REE were in fine class –0.02+0.01 mm, –0.01+0.005 mm and less than 0.005 mm. Large classes were characterized by the presence of grains of minerals of low specific gravity with a reduced REE concentration, which determined the possibility of removing depleted fractions by gravity methods. To assess the possibility of using gravity technology for the enrichment of rare earth ore from the weathering mantle of the Kundybay deposit, a fractional analysis of the machine classes of crushed ore with a size of –2.50+0.315 mm and –0.315+0.10 mm was performed. The results of fractional analysis showed that REE were concentrated in minerals of increased density (more than 2850 kg/m3). Based on the results obtained, the possibility of extracting REE from both its slurry and sand fractions has been determined. For the studied ore of the Kundybay deposit, the use of a combined scheme is proposed, including gravitational enrichment of granular classes and subsequent hydro-and pyrometallurgical processing of enriched granular and slurry classes. Based on the conducted experimental and enlarged technological studies, the use of a bowl centrifugal separator in the process of gravitational enrichment is justified, which allows to intensify the extraction of minerals concentrating rare earth elements from relatively small ore classes. The application of the developed scheme using combined gravity enrichment technology with a combination of screw and bowl centrifugal separators ensures an increase in the content of ΣREE in gravity concentrate from 640 to 1054 g/t with the extraction of ΣREE into concentrate and industrial products of more than 70%. An additional economic effect is achieved by removing final tailings from the enrichment scheme and reducing by 30% the yield of products sent for hydrometallurgical processing.

Полупроводниковые наноструктурированные образцы ZnOи ZnO-GOбыли получены при комнатной температуре методом химического осаждения из раствора.В работе исследовано электрохимическое неферментативное определение аскорбиновой кислоты с помощью полученных наноструктур, нанесённых на стеклоуглеродный электрод. Морфология и структурные свойства изготовленных наноструктурированных материалов были проанализированы с помощью электронного растровогомикроскопа и рентгеновскогодифрактометра. Электрохимические свойствабыли исследованыметодами циклической вольтамперометрии на одноканальном потенциостате-гальваностате. Чувствительность полученных электродовбыла рассчитана для концентрацийаскорбиновой кислотыв фосфатно-буферном растворе от 0,3мМ до 3 мМ при различных скоростях сканирования. Таким образом,было выявлено, что чувствительность образца ZnO-GO ниже, чем у образцаZnO, что может быть связано с диэлектрическими свойствами оксида графена. Однако после отжига в атмосфере чувствительность образца ZnO-GO повысилась, что связано суменьшением дефектов в образце и увеличениемудельной поверхности образцов. В результате исследованийбыл получен модифицированный ZnO-GO/GCE электрод с высокой чувствительностью 386 мкАМ-1см-2,перспективный для использования в качестве основы биосенсора для определения уровнявитамина C вкрови,пищевых продуктах и лекарствах.

Strength and stiffness assessment of rod mechanisms and robotic manipulators is commonly performed using finite element methods (FEM), while motion-induced inertia is often represented by resultant forces and moments applied at link centers of mass. This simplification is inherently approximate because inertial and gravitational forces are distributed along the link and depend on instantaneous kinematics. The main contribution of this paper is a systematic FEM-ready algorithm that extends a previously planar distributed-inertia concept to a formulation applicable to both planar and spatial rod models. The proposed approach computes distributed inertial and weight load intensities in the local coordinate system of each moving rod from kinematic quantities (link orientation, angular velocity/acceleration, and pole accelerations), transforms them into consistent equivalent nodal forces and moments, and assembles them into the global FEM equilibrium system for strength and stiffness calculations. Unlike flexible multibody dynamics formulations (e.g., floating frame of reference formulation (FFRF)/ANCF) absolute nodal coordinate formulation, which primarily target time-domain dynamic simulation, the proposed method is design-oriented and directly produces configuration-dependent engineering outputs-bending moments, axial forces, and longitudinal/transverse displacements-required for link cross-section sizing and stress assessment. The method is demonstrated on a six-bar planar mechanism to illustrate the influence of distributed inertia on internal force and deformation diagrams at low and high driving speeds.

Improving the durability of reinforced concrete sleepers is essential for railway infrastructure exposed to dynamic loading, moisture, and repeated freeze–thaw action. This study proposes a material-level modification approach for heavy concrete for type 2 reinforced concrete sleepers based on the combined use of activated microsilica, a ferroalloy-production byproduct, electrolyzed mixing water, and a polycarboxylate superplasticizer. The novelty of the work lies in the preliminary electrochemical activation of microsilica in an alkaline medium and in the optimization of its joint use with KN-5 by means of second-order experimental design. The concrete was evaluated by compressive and bending strength tests, scanning electron microscopy (SEM), water-penetration testing, and freeze–thaw resistance testing. All modified mixtures outperformed the reference concrete. The highest 28-day compressive strength reached 67.0 MPa, while bending strength reached 7.26 MPa. SEM observations showed a denser and more homogeneous cement matrix with reduced capillary porosity and improved interfacial transition zones. Water resistance improved from W8 for the reference mixture to W10–W14 for the modified concretes. Most modified mixtures achieved a frost resistance grade of F500, and the composition containing 15% activated microsilica and 1.0% superplasticizer reached F550. The proposed approach is effective at the material level for producing heavy concrete with enhanced strength and durability characteristics for reinforced concrete sleeper applications.

The relevance of the topic is due to the need to design and construct foundations in conditions of dense urban development and weak soils. The aim of this work is to study the features of pile foundation design, taking into account the stability of the excavation and the effect of phased loading on foundation settlement. The novelty of the research lies in the numerical modeling of phased construction using a wall in the ground, as well as the analysis of changes in the stress-strain state of the foundation, taking into account the stages of pile installation. Calculations performed in the Plaxis 2D software environment showed that when a five-story building is fully loaded, the foundation settlement does not exceed 1 cm, which is within the maximum permissible values according to the standards. The maximum horizontal displacement of the enclosing wall was 0.45 cm, which also indicates its stability at an excavation depth of up to 3 m and the presence of anchors. The results confirm the effectiveness of the combined system—walls in the ground, anchors, and pile foundations—when building on weak soils in confined conditions. The work is of practical value for the engineering and geotechnical justification of construction solutions in densely built-up areas.

Оқулықта алюминий металлургиясының негіздері, оның қасиеттері, қолдану салалары және алюминий тотығы мен түпкілікті өнім – тауарлық алюминий өндірісінің теориясы мен технологиясының негізгі ережелері келтірілген. Алюминийді сынықтар мен қалдықтардан, алюминий өнеркәсібінде жолай түзілетін аралық өнімдерді қайта өңдеу сұрақтары қамтылған. Сонымен қатар, алюминий тотығы мен металдық алюминийді өндірудің негізгі процестерінің материалдық баланстарының егжей-тегжейлі есептеулері ұсынылған. Оқулық 6В07203 – «Металлургия және пайдалы қазбаларды байыту», 6В07219 – «Түсті металдар металлургиясы», 6В07212 – «Металлургиядағы рециклинг» білім беру бағдарламалары бойынша оқитын білім алушыларға арналған. Сонымен қатар, зауыттардың инженерлік-техникалық қызметкерлеріне пайдалы болуы мүмкін. Кесте 70, сурет 71, әдебиеттер атауы 14.

The article focuses on the study of the processes intended for copper smelting slag processing, in order to extract such valuable components as copper, zinc, iron and silica. Various options for slag leaching with the use of sulfuric acid as one of the most promising approaches are considered. Preliminary thermodynamic calculations confirmed the high probability of dissolution of metal oxides when interacting with sulfuric acid. High-temperature leaching resulted in higher recovery rates for copper and other valuable metals. The use of sulfuric acid at the concentration of 50 g/dm3 in combination with the optimization of leaching parameters provided the high efficiency of valuable metal extraction—copper up to 76%, zinc up to 94% and iron in the form of oxide up to 92%. Acceleration of pulp filtering was achieved through two-stage re-pulping with hot water. The study results confirm the prospects of hydrometallurgical methods of slag processing. It opens up opportunities for the development of more efficient technologies for processing copper smelting waste, aimed at maximum extraction of useful components at minimal costs.

The rapid advancement of high-technology industries critically depends on the supply of rare earth elements (REEs), which constitute strategic raw materials for knowledgeintensive sectors. This study proposes an integrated methodological framework for the development of the Kundybay REE deposit, combining geomechanical substantiation of open-pit slope stability with beneficiation optimization of weathering-crust ores. The novelty of the research lies in the justification of rational pit-wall parameters based on a coupled 3D geological–geotechnical model implemented in the Micromine environment. Structurally disturbed zones were identified and subjected to detailed stability analysis using numerical modeling techniques. Particular emphasis was placed on the delineation of geotechnical domains and factor-of-safety evaluation in Slide2, which enabled refinement of design solutions and optimization of slope geometry. Simultaneously, the study addresses processing challenges of refractory weathering-crust ores through the application of ultrasonic aerohydraulic desliming combined with a vibro-centrifugal separation device. Optimization of slope parameters resulted in a 30 Mt reduction in stripping volume, corresponding to a 16.7% economic gain. The proposed flowsheet achieved a concentrate grade of 948.89 g/t REEs with an overall recovery of 45.66%. The results confirm that integrating geomechanical design with process engineering provides a technically robust and economically efficient basis for REE deposit development.

The article presents experimental data on the electrochemical oxidation of vanadium-bearing ore with the aim of increasing the efficiency of vanadium extraction during subsequent hydrometallurgical processing. Three different charge compositions were studied during the preliminary oxidative roasting stage, differing in the type of oxidizers used: calcined soda, sodium chloride, and their mixture in a mass ratio of 9:1. Electrochemical oxidation was carried out in a sulfuric acid medium using a membrane electrolysis cell equipped with an MK-40 type diaphragm. Experimental studies were conducted by varying key technological parameters: H2SO4 concentration (5–15%), solid-to-liquid phase ratio (1:2–1:5), temperature (25–85 ◦C), process duration (0.5–3 h), and current density (100–1000 A/m2 ). It was found that preliminary roasting promotes the conversion of vanadium into higher oxidation states, predominantly V5+, which significantly increases its solubility during subsequent electrochemical treatment. For the first time, the kinetic patterns of electrochemical vanadium leaching were identified, as well as the limiting mechanism of the process, associated with the formation of poorly soluble oxide films on the ore surface. Optimization of the electrochemical oxidation parameters allowed us to achieve vanadium extraction into solution up to 92%.

Industrial technologies for processing tungsten concentrates using soda roasting or autoclave leaching are based on the production of alkaline sodium tungstate solutions that contain impurities such as silicon, phosphorus, arsenic, and others. The purification of these solutions from impurities requires the neutralization of excess soda or alkali with inorganic acids, which leads to the formation of chloride and sulfate effluents that are subsequently discharged into waste repositories. An analysis was carried out on existing methods for the production and processing of sodium tungstate solutions using HNO3 and NH3, as well as extraction and sorption techniques involving anion exchange resins. Currently, processes such as nanofiltration, reverse osmosis, and electrodialysis are being applied for water purification and the treatment of sulfate and chloride effluents. These processes employ various types of industrially manufactured membranes. For the purpose of electrodialysis, a two-compartment electrodialyzer setup was employed using cationexchange membranes of the MK-40 (Russia) and EDC1R (China) types. The composition and structure of sodium tungstate, used as the starting reagents, were analyzed. Based on experiments conducted on a laboratory-scale unit with continuous circulation of the catholyte and anolyte, dependencies of various parameters on current density and process duration were established. Stepwise changes in the anolyte pH were recorded, indirectly confirming changes in the composition of the Na2WO4 solution, including the formation of polytungstates of variable composition and the production of H2WO4 via electrodialysis at pH < 2. The resulting tungstic acid solutions were also analyzed. The conducted studies on the processing of sodium tungstate solutions using electrodialysis made it possible to obtain alkaline solutions and tungstic acid at a current density of 500–1500 A/m2 , without the use of acid for neutralization. Yellow tungstic acid was obtained from the tungstic acid solution by evaporation.